Pressure regulating valve for pumps



1954 I c. ,8. LIVERS 2,691,388

PRESSURE REGULATING VALVE FOR PUMPS Filed Jan. 8, 1952 INVENTOR.

0.8. ivers BY L ATTORNEY Patented Oct. 12, 1954 PRESSURE REGULATING VALVE FOR PUMPS Carlos B. Livers, North Hollywood, Calif., assignor to Bendix Aviation Corporation, North Hollywood, Calif., a corporation of Delaware Application January 8, 1952, Serial No. 265,451

2 Claims.

This invention relates to pumping systems for sup-plying pressure fluid at a predetermined maximum pressure, and more particularly to a valve structure for automatically throttling the suction line of the pump when the output pressure tends to exceed the predetermined maximum pressure.

An object of the invention is to provide a simple and inexpensive, yet reliable valve for III ' 2 and prevent its free movement. The left end of the bore 2! communicates with a chamber 28 which in turn is communicated by a passage 29 with the discharge manifold I5 of the pump. A cup-shaped screen 39 is provided in the chamber 2S to prevent solid particles in the fluid from reaching the piston 26. Such particles might tend to prevent free action of the piston. The screen 39 may be retained in sealing engagement the purpose stated. with the right end of the chamber 23 by a heli- Another object is to provide an inexpensive cal compression spring 3| compressed between the valve for the stated purpose that maintains good left end of chamber 28 and an outwardly extendregulation of the pump output pressure. ing flange 3011 on the right end of the screen 30. The foregoing together with more specific ob- The area of the piston 26 is so proportioned jects and features of the invention will become relative to the spring 25 that the spring 25 mainapparent from the description to follow. tains the valve member It in open position away The single figure of the drawing is a schematic from the sealing surface 24 except when the presdiagram showing a pump equipped with a valve in sure in the discharge manifold it rises to a preaccordance with the invention. determined. value, whereupon the force acting on d Refteriring to the draawing, thebpumlp dthierein g izilge lefit end ofttrliie piston 26 og ei'iloniis th lslpring epic e comprises a ody mem er e ning e an moves e va ve mem er 0 e rig t unthree pump cylinders 2, 3 and i, respectively, contil its open end engages and seals with the annutaining plungers or pistons 5, 6 and l respectivelar sealing surface 24. 13;, which are actuated by eccentrics 8, 9 and Ill It Will be observed that when the poppet l9 respectively, on a common drive shaft ll. Each 25 is in open position, as shown, there is a free pasof the pump cylinders 2, 3 and i is provided with sageway for fluid from the inlet port ll, past the a spring-closed intake valve l2 which connects right end of the valve member [9, into the annuit with a common intake passage or manifold M, lar port 22 and thence into th intake manifold andba spring-closed exhausg valllve it which conllll where it is supplied through the inlet valves 1160's it with a common isc arge passage or 2 to the three pump cylinders. However, manifold It. Th discharge manifold I5 is to be whenever the pressure rises above the predeter connected directly to the load to be supplied from mined desired value in the exhaust manifold IS, the pump. Themtake manifold I4 is adapted to the piston 26 is moved to the right, moving the be connected directly to an inlet port ll by a valve member It with it, until the latter seals with valve in accordance with the invention. the annular sealing surface 24, thereby prevent- This valve comprises a hollow, cup-shaped ng further entry of fluid from the intake pascylindrical valve member is closed at its left end sage l7 into the intake manifold M, whereupon excrept far a 1fluid passage 1205, and open 1at its the pump pistons 5, 6- and l reciprocate without rig t en T e valve mem er is in siding, pumpin any fluid, simply drawing a vacuum sealing engagement with a cylinder 2| formed in 40 in the pamp cylinders and the intake manifold M. the bodc lr At its right endl, the cyliznzder 2| is b Tche success (if the valvetdesoribed appears tr; en arge o provi e an annu ar por in cone ue in part 0 i s poppe action and the fac stant communication with the intake passage 54 that all pressure forces on the valve member [9 leading to the pump. The right end of th cylinare balanced. The poppet action of the valve cler 2i defines an annular stationary sealing surmakes it impossible for the valve to over-shoot face 241 surrounding the intake port l7. Aspring beyond closed position, since, when the valve 25 is contained within the valve member l9 and member closes against the sealing surface 24 it is compressed between the left end of the valve is incapable of any further movement, and remember and the right end of the cylinder 2! mains in that position until the pressure in the The valve member 19, at its left end, bears discharge manifold IE and. the chamber 28 drops against a cighndrcia rod Zia Wl1l10hhCOnt1tlltE a to a value hsuffficlent to permiththe spring 25 to pis on in a ore ormet in e ousing. novercome e orce actin on t e left end 0 the nular grooves 26a are preferably provided on the piston 26, and again opei i the valve. f piston 26 to facilitate the circumferential equali- Effective pressure balanc on the valve mem zation of pressure fluid on the piston and preher I9 is attained in all positions. Thus it will vents lateral forces which would tend to bind it be observed that any axial pressure on the right end of the valve member is substantially balanced by an equal and opposite pressure on the left end, because of the connecting port 20 in the valve member. It is impossible for any unbalanced lateral forces to be produced, because the fluid passages or chambers associated with the valve member l9 are all symmetrical about the axis of the valve'memb'er. When the valve member 19 is closed on'the annular sealing surface 24, and the pump is operating to draw a vacuum in the intake manifold 14, a substantial difference of pressure exists between the-inside and-the outside of the poppet. However this pressure acts symmetrically radially in all directions and cannot tend to cause the valvemembe'r to bind in the cylinder 2 l.

In valves of this type adapted for operation at relatively high pressures it is often difficult to secure a spring of sufficient stiffness and low spring rate to balance the pressures that are involved. This problem is solved in the present invention by virtue'of the "fact that the piston 28, which is exposed to thedischarge pressure of th pump, can be of relatively small diameter as compared to the diameter of thepoppet l9,'and the-springracan be of relatively large diameter andlength as compared to the diameter of the piston 26.

Although for the purpose of explaining the invention a particular embodiment thereof has been shown and described, obvious modifications will occur to a person skilled in theart, and I do not desire to'be'limited'to the exact details shown and 'described.

I claim:

1. A pressure responsive flow regulating valve comprising: means defining a cylinder having an end port at one end and an annular port in its peripheral wall adjacent said one end, having an annular sealing surface surrounding said end port, and having a cylindrical bore of substan- "spaced from said sealing surface in the other,

open, end position, the other closed end of said valve member facing said bore; a helical compression spring extending and compressed between the closedend of said valve member and said one end of said cylinder for urging said valve member in opening direction; a piston reciprocalole in said bore in sealing relation therewith and extending therefrom into said cylinder in contact with said closed end of said valve member, whereby the opening force of said spring'on the valve member isopposed by the pressure-force on said piston of fluid pressure in said chamber; and passage means communicating said other end of said cylinder with saidend port for equalizing the pressures on opposite faces of said valve member end wall. H

2. A valve according to claim 1 in which the diameter of that portion of said valve member that seals with said annular sealing surface is substantially the diameter ofsaid cylinder.

References'Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,089,397 Conrader Mar. 10, 1914 2,059,808 Robai't'et a1. Nov.-3, 1936 2,583, 96 Harrington Jan. 22, 1952 2590333 Boggs Apr. 1, 1952 

